Warp beam take-off drive



Dec. 24, 1968 E. GATTIKER WARP BEAM TAKE-OFF DRIVE Filed March 1, 1967 INVENTOR. W 294% BY United States Patent 3,417,791 WARP BEAM TAKE-OFF DRIVE Ernst Gattiker, Thurgau, Switzerland, assignor to Adolph Saurer Ltd., Thurgan, Switzerland Filed Mar. 1, 1967, Ser. No. 619,804 Claims priority, application Switzerland, Mar. 28, 1966, 4,456/ 66 9 Claims. (Cl. 139109) ABSTRACT OF THE DISCLOSURE A control roller extends across the pile warp unwound by transporting rollers from a pile warp beam, and exerts an unwinding force on the same. Levers supporting the roller are connected with a brake for braking the warp beam with a brake torque depending on the tension of the warp.

Background of the invention The present invention relates to a warp beam take-off drive, and more particularly to the take-off drive of a pile warp beam of a pile fabric loom.

In accordance with prior art constructions for controlling the take-off operation, the transporting rollers transport the pile warp which is wound up on the pile warp beam whereby the pile warp beam is rotated, without requiring drive means of its own. This type of take-off drive has disadvantages inasmuch as upon start of the transporting rollers, the turning movement of the pile warp beam is started with a jolt since its great inertia has to be overcome. Before the pile warp beam starts to rotate, the warp portion between the pile warp beam and the transporting rollers is excessively tensioned, while upon start of the rotation of the pile warp beam, the same turns too fast due to its inertia, and causes slackening of the warp before the slack is taken up by the transporting rollers. Another disadvantage is the necessity of regulating the brake of the warp beam depending on the diameter of the warp package wound up on the warp beam to avoid varying tensioning of the warp which has a detrimental effect on the fabric produced by the loom, particularly if the warp is the pile warp of a pile fabric.

Another prior art construction provides a horizontally movable pendulum roller which permits to move a certain length of the warp ahead. In this construction, an electrornotor drives the warp beam positively through a worm gear drive until the pendulum roller arrives at one end position and stops the motor by operating a limit switch. The warp beam rotation is thus blocked, and the transporting means transports the portion of the warp which is controlled by the pendulum roller only so that only the resistance of the same has to be overcome. When the slack of the warp is taken up, and the roller arrives in its other end position, another limit switch is actuated and the electromotor is started so that the operation is repeated. This prior art construction has the disadvantage that a drive motor for the warp means is required.

Summary of the invention It is one object of the invention to overcome the disadvantages of the prior art take-off drive for warp beams, and to provide a simple and efiicient construction for preventing excessive tensioning or slackening of a warp taken off a warp beam.

Another object of the invention is to use the tension of the warp for controlling a brake acting on the warp beam.

With these objects in view, the present invention is concerned with a warp beam take-off drive which comprises a warp beam and transporting means for unwinding a warp from the warp beam so that the unwinding torque rotates the warp beam.

One embodiment of the invention comprises brake means for braking the warp beam with a variable braking torque opposed to the unwinding torque, and movable control means disposed intermediate the warp beam and the transporting means and applying a force to the same which is caused by the weight of the control means, and by a spring acting on the same.

This force produces an'additional unwinding torque on the warp beam. The control means is operatively connected with the brake means and operates the same so that the brake torque is reduced when the control means is displaced in one direction by the warp tensioned by the transporting means, and is increased when the warp slackens whereby the warp beam continuously rotates at a substantially constant speed.

Preferably, the weight of the control means, or the biassing force of its spring, is selected so that the brake torque is equal to the unwinding torque produced by the control means when the transporting means is at a standstill.

In the preferred embodiment, the control means includes lever arms supporting a control member in the form of a roller extending across the warp and resting on the same, and the brake means has an adjusting lever connected by a linkage with the lever arms. The brake means is preferably a friction brake having a brake band connected to the adjusting lever, however, in a modified embodiment, an electromagnetic brake is used for braking the warp beam, and has a circuit including a pair of limit switches operated by a part of the control means.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

Brief description of the drawing The single figure of the drawing is a side elevation illustrating an embodiment of the invention in which a mechanical friction brake is used.

Description of the preferred embodiments Referring now to the drawing, a pair of upright supports 2 is mounted at the rear end of the frame 1 of a pile fabric loom. A base warp 5 of a pile fabric is transported along frame 1 and is combined with the pile warp 4 which is unwound from a warp beam 3 on which the warp 4 is wound up in the form of a reel or package 4a. Warp beam 3 is mounted in bearings on supports 2 which also support a driving and transporting roller 6, and a pair of guiding rollers 7 and 8 cooperating drive roller 6 to transport the pile warp 4 so that the same is unwound from the warp beam 3. Double armed lever means 11 are mounted on support means 2 in bearings 9 and have arm means 11b rotatably carrying a control roller 14 which rests in an open loop of pile warp 4 and extends across the same. Arm means 11b preferably include a pair of arms 11b, 11b" pivotally mounted in bearings 9 and having free ends connected by a shaft on which roller 14 is mounted between the free ends of lever arms 11b, 1111". Due to its weight, control roller 14 is biased by gravity and exerts a tensioning force on the portion of the warp between warp beam 3 and transporting means including a plurality of horizontal driving end guiding rollers 6, 7, 8. If the weight of control roller 14 is not suflicient, a torsion spring 11a, acting on lever means 11, is provided to increase the force applied by control roller 14 to warp 4.

Warp beam 3 carries a brake drum 16 over which a brake band 15 passes. One end 17 of the brake band is secured to support means 2 and fixed, while the other end of the brake band has a pair of stop members 18 and 19 between which a coil spring 20' is disposed. An adjusting lever 12 for brake 15, 16 is mounted for turning movement in a bearing of support means 2 and has an arm located between stop 18 and spring 20, and another arm connected by a linkage 13 to the second arm means 110 of double armed lever means 11.

The weight or the spring force acting on control roller 14 exerts a tensioning force on warp 4 in the unwinding direction which urges the yarn package 4a and warp beam 3 to rotate in counterclockwise direction. At the same time, control lever means 11 controls the adjusting lever 12 of brake 15, 16 to produce a brake torque opposing the unwinding torque produced by control roller 14. The ratio between the lever arms, and the weight or spring force of control roller 14 are so selected that, when rollers 6, 7, 8 are not operated, the brake torque balances the unwinding torque produced by control roller 14. Consequently, the warp beam does not turn when driving roller 6 is not driven.

When the motor of driving roller 6 is started, the warp 4 is transported and an unwinding torque is produced which turns warp beam 3 in counterclockwise direction so that the reel 4a consisting of the spirally wound warp is unwound. The tension in warp 4 produced by rollers 6, 7, 8 has the tendency to flatten the open loop in warp 4 so that control roller 14 is raised and lever means 11 turns in clockwise direction to turn adjusting lever means 12 of brake 15, 16 in the same direction which causes lever 12 to engage stop 18 and to loosen the tension of brake band so that the brake torque is reduced which permits starts of rotation of warp beam 3 without any sudden jolt. The rotating warp beam turns reel 4a so that the same supplies an additional length of warp 4 to the open loop therein, permitting control roller 14 to move down which causes actuation of lever 12 by link 13 in counterclockwise direction so that brake band 15 is gradually tightened by spring 20 pressed against stop 19.

During continuous weaving operations, driving roller 6 is successively started and stopped, and after several operations of control means 11, 14, brake means 15, 16 has adjusted the rotary speed of warp beam 3 so that the same slowly and continuously rotates while the tension of the portion of warp 4 between rollers 6, 7, 8 and warp beam 3 remains constant Without any additional adjustment. While the rotation of warp beam 3 is still due to the unwinding torque of Warp 4 produced by driving and guiding rollers 6, 7, 8, the tension of warp 4 is held constant by slow movement of the control means.

In a modified embodiment of the invention, the mechanical friction brake is replaced by an electromagnetic brake in whose exciting circuit two limit switches are provided for energizing and deenergizing the electromagnetic brake. The limit switches are operated by lever means 11 which may be constructed as a pair of levers respectively pivotally mounted on support 2 and connected by a shaft on which control roller 14 is mounted for rotation. In this modified embodiment, increased tension of warp 4 will raise control roller 14 so that one of the limit switches is actuated to de-energize the electromagnetic brake permitting a greater length of warp 4 to be supplied to the transporting rollers. When the additionally supplied length of warp 4 causes lowering of control roller 14, the other limit switch is actuated to energize the brake and thus cause driving and guiding rollers 6, 7, 8 to take up the slack of the warp portion between reel 4a and the tranporting rollers.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of warp beam take-off drives differing from the types described above.

While the invention has been illustrated and described as embodied in a warp beam take-01f drive having control means for producing an additional unwinding torque on the warp and controlling the brake of the warp beam, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the follovw'ng claims.

What is claimed .as new and desired to be protected by Letters Patent is set forth in the appended claims.

I claim:

1. A warp beam take-01f drive comprising, a warp beam mounted for rotation; transporting means for unwinding a warp from said warp beam whereby an unwinding torque is applied to said Warp beam and the same is rotated, said transporting means including a plurality of horizontal guiding and driving rollers over which said warp is guided; brake means for braking said warp beam with a variable braking torque opposed to said unwinding torque; and control means including a horizontal control member mounted for upward and downward movement and disposed intermediate said warp beam and said guiding and driving rollers substantially adjacent to the same and below the same resting on said warp due to the force of gravity whereby a loop open on top and supporting said control member at the lowest point thereof is formed in said warp and an additional unwinding torque is applied to said warp beam; and connecting linkage means operatively connecting said control means 'with said brake means for operating the same depending on the position of said control member so that said brake torque is reduced when said control member is raised against the action of garvity when said warp is tensioned by said transporting means and the size of said loop is reduced, and so that said brake torque is increased when said control member is moved downward by the action of the force of gravity and increases the size of said loop when said warp slackens whereby said Warp beam rotates at a constant speed.

2. A warp beam take-off drive as defined in claim 1 wherein said control member extends across said warp, and torsion spring means aiding in the biasing of said control member toward said warp.

3. Warp beam take-off drive as claimed in claim 1 wherein said brake rneans include a brake for said warp beam, and adjusting means for said brake connected by said connecting linkage means with said control means, said adjusting means including an adjusting member connected with said brake, and a spring means connecting said adjusting member with said connecting linkage means so that movements of said control member and of said control means are transmitted by said connecting linkage means and said spring means to said adjusting member of said brake.

4. Warp beam take-off drive as claimed in claim 3 wherein said control means include movable lever means having a horizontal axis and supporting said control member for up and down movement, wherein said adjusting member has a stop and mounts said spring means abutting said stop; and wherein said connecting linkage means includes a lever connected with said spring means for urging the same against said stop for operating said adjusting member.

5. A Warp beam take-0E drive as defined in claim 1 whereinsaid brake means is arranged and constructed, and said force is selected so that said brake torque is equal to said additional unwinding torque when said transporting means is at a standstill whereby said warp beam is not rotated by said force of said control means when said transporting means is not operated.

6. A Warp beam take-off drive as defined in claim 1 wherein said control means includes a control member extending across said warp, lever means pivotally mounted for angular movement and supporting said control member; wherein said brake means include pivotally mounted adjusting means; and comprising linkage means connecting said lever means with said adjusting means for angular movement.

7. A warp beam take-01f drive as defined in claim 6 wherein said lever means includes a pair of double armed levers having a pair of arms constituting said arm means and supporting said control member bet-ween each other; wherein said adjusting means includes an adjusting lever means; and wherein said linkage means connects said at least one arm of said double armed levers with said adjusting lever means.

8. A Warp beam take-off drive as defined in claim 7 References Cited UNITED STATES PATENTS 1,539,178 5/1925 Giardino 139-102 2,397,914 4/1946 Blouin l39109 2,705,024 3/1955 Beer l39l09 FOREIGN PATENTS 538,276 6/1955 Belgium. 1,092,501 11/1954 France.

HENRY S. IAUDON, Primary Examiner. 

